Minor fix in web-ext-lint job description

Change-Id: I12f034712cffacf57ae7b3b717d6f78478e1dbbf
diff --git a/zuul.d/jobs.yaml b/zuul.d/jobs.yaml
index b3f6cbc..e60881d 100644
--- a/zuul.d/jobs.yaml
+++ b/zuul.d/jobs.yaml
@@ -3,4 +3,7 @@
     pre-run: playbooks/web-ext-lint/pre.yaml
     run: playbooks/web-ext-lint/run.yaml
     post-run: playbooks/web-ext-lint/post.yaml
-    description: ".. include:: ../playbooks/web-ext-lint/README.rst"
+    description: |
+      Check a Web Extension project for basic lint problems.
+
+      .. include:: ../playbooks/web-ext-lint/README.rst